Radar wear sensing for tire applications

ABSTRACT

A radar-based-sensing system for a tire includes a plurality of sensors disposed circumferentially around a tire annulus. Each sensor in the plurality of sensors is permanently disposed within the tire annulus. Each sensor in the plurality of sensors is further disposed radially above any metal structures within the tire annulus. Each sensor in the plurality of sensors emits waves and senses reflected waves when rotating.

FIELD OF INVENTION

The present disclosure is directed to tires and tire treads featuringwireless sensors and tires and tire systems that use and incorporatewireless sensors. More particularly, the present disclosure is directedto tires and tire systems that sense tread wear. The tires may bepneumatic or non-pneumatic.

BACKGROUND

Known low-power, wireless sensors emit electromagnetic waves and receivereflected electromagnetic waves to approximate a distance from anobject. The sensors lack a power source, and are thus used inconjunction with interrogators. The interrogators power the wirelesssensors and communicate measurements to additional components within asystem.

SUMMARY OF THE INVENTION

In one embodiment, a tire structure includes a first annular bead and asecond annular bead. A body ply extends between the first annular beadand the second annular bead, and a circumferential belt is disposedradially above the body ply and extends axially across a portion of thebody ply. A circumferential undertread is disposed radially above thecircumferential belt and extends axially across a portion of the bodyply. A first sidewall extends between the first annular bead and a firstshoulder. A second sidewall extends between the second annular bead anda second shoulder. The first and second shoulders are associated withthe circumferential undertread. An electronic device is disposedradially between the circumferential belt and a bottom tread surfacesuch that wear does not disable or damage the electronic device. Theelectronic device includes an emitter configured to emit pulsedelectromagnetic waves having a frequency between 30 and 300 GHz and abandwidth between 15 and 35 ps. The electronic device also includes areceptor configured to receive reflected electromagnetic waves and aprocessor that compares at least one property difference between anemitted and reflected wave. The electronic device further includes atransmitter configured to transmit data to an interrogator. Theelectronic device observes wear over the life of the tire, atsub-millimeter resolution.

In another embodiment, a radar-based-sensing system for a tire includesa plurality of sensors disposed circumferentially around a tire annulus.Each sensor in the plurality of sensors is permanently disposed withinthe tire annulus. Each sensor in the plurality of sensors is furtherdisposed radially above any metal structures within the tire annulus.Each sensor in the plurality of sensors emits waves and senses reflectedwaves when rotating.

In yet another embodiment, a wear-sensing radar and interrogatorassembly includes a tire having a first annular bead and a secondannular bead. A body ply extends between the first annular bead and thesecond annular bead. A circumferential belt is disposed radially abovethe body ply and extends axially across a portion of the body ply. Acircumferential tread is disposed radially above the circumferentialbelt and extends axially across a portion of the body ply. A firstsidewall extends between the first annular bead and a first shoulder. Asecond sidewall extends between the second annular bead and a secondshoulder. The first and second shoulders are associated with thecircumferential tread. At least one radar device is embedded in thetire, between the circumferential belt and voids in the circumferentialtread. The at least one radar device emits and receives radar waveshaving a frequency between 90 and 100 GHz. At least one interrogator isconfigured to power and receive data from the at least one radar device,wherein the interrogator is not disposed on the tire.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, structures are illustrated that, togetherwith the detailed description provided below, describe exemplaryembodiments of the claimed invention. Like elements are identified withthe same reference numerals. It should be understood that elements shownas a single component may be replaced with multiple components, andelements shown as multiple components may be replaced with a singlecomponent. The drawings are not to scale and the proportion of certainelements may be exaggerated for the purpose of illustration.

FIG. 1 is a peel-away cross-sectional perspective view of an embodimentof a tire structure;

FIG. 2 is partial a cross-sectional view of an alternative embodiment ofa tire structure;

FIG. 3 is a perspective view of one embodiment of a tire system, and;

FIG. 4 is a perspective view of radar and interrogator assembly.

DETAILED DESCRIPTION

The following includes definitions of selected terms employed herein.The definitions include various examples and/or forms of components thatfall within the scope of a term and that may be used for implementation.The examples are not intended to be limiting. Both singular and pluralforms of terms may be within the definitions.

“Axial” and “axially” refer to a direction that is parallel to the axisof rotation of a tire.

“Circumferential” and “circumferentially” refer to a direction extendingalong the perimeter of the surface of the tread perpendicular to theaxial direction.

“Radial” and “radially” refer to a direction perpendicular to the axisof rotation of a tire.

“Sidewall” as used herein, refers to that portion of the tire betweenthe tread and the bead.

“Tread” as used herein, refers to that portion of the tire that comesinto contact with the road or ground under normal inflation and normalload.

“Tread width” refers to the width of the ground contact area of a treadwhich contacts with road surface during the rotation of the tire undernormal inflation and load.

Directions are stated herein with reference to the axis of rotation ofthe tire. The terms “upward” and “upwardly” refer to a general directiontowards the tread of the tire, whereas “downward” and “downwardly” referto the general direction towards the axis of rotation of the tire. Thus,when relative directional terms such as “upper” and “lower” or “top” and“bottom” are used in connection with an element, the “upper” or “top”element is spaced closer to the tread than the “lower” or “bottom”element. Additionally, when relative directional terms such as “above”or “below” are used in connection with an element, an element that is“above” another element is closer to the tread than the other element.

The terms “inward” and “inwardly” refer to a general direction towardsthe equatorial plane of the tire, whereas “outward” and “outwardly”refer to a general direction away from the equatorial plane of the tireand towards the sidewall of the tire. Thus, when relative directionalterms such as “inner” and “outer” are used in connection with anelement, the “inner” element is spaced closer to the equatorial plane ofthe tire than the “outer” element.

While similar terms used in the following descriptions describe commontire components, it is understood that because the terms carry slightlydifferent connotations, one of ordinary skill in the art would notconsider any one of the following terms to be purely interchangeablewith another term used to describe a common tire component.

FIG. 1 is a peel-away cross-sectional perspective view of an embodimentof a tire 100. As shown, tire 100 features a first annular bead 105 anda second annular bead 110. The annular beads, in part, secure the tireto a wheel. In an alternative embodiment (not shown), the tire comprisesfour or more beads.

As shown, tire 100 further features a body ply 115 extending between thefirst annular bead 105 and the second annular bead 110. Body ply 115imparts shape to the tire. As one of ordinary skill in the art willunderstand, body ply 115 may contain reinforcing cords or fabric (notshown). In an alternative embodiment (not shown), the body ply forms aquick 2 construction.

Tire 100 further comprises a circumferential belt 120. Circumferentialbelt 120 is disposed radially above body ply 115 and extends axiallyacross a portion of body ply 115. As one of ordinary skill in the artwill understand, circumferential belt 120 may contain steel cords andreinforcing cords (both not shown). In an alternative embodiment (notshown), the circumferential belt lacks metal.

Tire 100 also further comprises a reinforcement ply 125. Firstreinforcement ply 125 is disposed radially above circumferential belt120 and extends axially across a portion of body ply 115. As one ofordinary skill will understand, additional reinforcement plies may beutilized. The reinforcement plies strengthen and stabilize the tire. Inalternative embodiments (not shown), the tire contains one or three ormore reinforcement plies. In another embodiment, the reinforcement pliesare omitted.

As illustrated in FIG. 1, tire 100 further comprises a cap ply 130. Capply 130 is disposed radially above circumferential belt 120 and secondreinforcement ply 130. Cap ply 130 extends axially across a portion ofbody ply 115. In an alternative embodiment (not shown), a sealing gellayer is provided in the cap ply region.

Tire 100 further comprises an undertread 135. Undertread 135 is disposedradially above circumferential belt 120 and cap ply 130. Undertread 135extends axially across a portion of body ply 115. Undertread 135 istypically comprised of rubber, and its thickness may vary depending ontire application. For instance, in retreading applications, a thickerundertread is desired to accommodate buffing. In passenger tireapplications, by comparison, a thinner undertread is desired.

As shown, tire 100 further comprises a first sidewall 140 and a secondsidewall 145. First sidewall 135 extends between the first annular bead105 and a first shoulder 150, which is proximately associated with anedge of circumferential tread 160. Second sidewall 145 extends betweenthe second annular bead 110 and a second shoulder 155, which isproximately associated with the opposite edge of circumferential tread160. In an alternative embodiment (not shown), the sidewall isproximately associated with an undertread (not shown). With continuedreference to FIG. 1, tire 100 further comprises a circumferential tread160, which is separated by circumferential grooves 165. Circumferentialtread 160 is disposed radially above reinforcement ply 125 and cap ply130, and circumferential tread 160 extends axially across a portion ofbody ply 115 and between the shoulders 150, 155. In the illustratedembodiment, circumferential grooves 165 divide circumferential tread 160into five ribs. However, it should be understood that any number of ribsmay be employed. In an alternative embodiment (not shown), tread blocksform the surface of the circumferential tread. In another embodiment,lugs form the surface of the circumferential tread. In a differentembodiment, a slick surface forms the surface of the circumferentialtread. As one of ordinary skill in the art will understand, tiresfeaturing a slick surface are suited for applications requiring highgrip, such as an airplane or racing tire might require.

Tire 100 further comprises an electronic device 170. Electronic device170 is disposed radially between circumferential belt 120 and thesurface of circumferential tread 160. More specifically, in theparticular embodiment shown in FIG. 1, electronic device 170 is disposedradially between undertread 135 and a radially inner portion ofcircumferential tread 160. As depicted, electronic device 170 is acylinder, but electronic device 170 is not limited to cylindrical forms.Electronic device 170 is secured within tire 100 by vulcanization,adhesives, patches, barbs, or through other means and methods known toone of skill in the art. Because electronic device 170 is secured withinthe tire, it does not move within the tire. The electronic device alsodoes not escape, eject from, or leave the tire after the initial amountof wear, and it does not intentionally cease operation when it is erodedor compromised. Thus, ordinary tread wear does not disable or damage theelectronic device. In an alternative embodiment (not shown), theelectronic device is disposed within the undertread. In anotherembodiment, the electronic device is disposed such that no metalstructures are disposed between the electronic device and the treadsurface. In a specific alternative embodiment, the electronic device isdisposed between 5 and 15mm of an inner surface of the body ply (e.g.,an innerliner).

In a retread embodiment, the electronic device is disposed between atire casing and a retread. In retread applications, the electronicdevice may be resettable or rewriteable to accommodate new treadinformation.

As depicted, electronic device 170 is disposed under a central rib onthe middle third of the tread width. However, the electronic device isnot limited to a particular axial location. Thus, in an alternativeembodiment (not shown), the electronic device is disposed under acircumferential groove in the circumferential tread. In anotheralternative embodiment, the electronic device is disposed under an outerthird of the tread width. In yet another embodiment, multiple electronicdevices may be employed at any locations. For example, a firstelectronic device may be disposed under a middle third of the treadwidth and a second electronic device is disposed under an outer third ofthe tread width. As another example, an electronic device may bedisposed under each rib in a tread pattern.

In one embodiment, the electronic device comprises an emitter, areceptor, a processor, and a transmitter configured to transmit data toan interrogator.

The emitter is configured to emit pulsed electromagnetic waves having afrequency between 30 and 300 GHz and a bandwidth between 15 and 35 ps.In an alternative embodiment, the pulsed electromagnetic waves have afrequency between 90 and 100 GHz, and have a bandwidth between 20 and 30ps. In another embodiment the pulsed electromagnetic waves have abandwidth between 24 and 26 ps. Although not shown, the emitter has amaximum range of about 1 meter. In another embodiment, the emitter has amaximum range of about 3 meters.

The receptor is configured to receive electromagnetic waves,particularly reflected electromagnetic waves. The electromagnetic wavesare emitted from the emitter, through a tire tread. The waves thenreflect off a surface on which the tire rests (i.e., a road or theground). The reflected waves are then received by the receptor. Theprocessor then compares at least one property difference between anemitted and reflected wave. A difference between the emitted andreflected waves is calculated, and this information is sent to aninterrogator. In either embodiment, a difference between the emitted andreflected wave is processed in an algorithm, which is used to calculatethe distance between the sensor and the reflection surface. Byextension, a remaining tread depth in a tire tread or an amount of treadwear is calculated. In this regard, the electronic device is able toobserve wear of a tire tread over the life of the tire tread, at sub-millimeter resolution. This information, which can be provided in realtime, may be sent through an interrogator for recordation or display.

In an alternative embodiment, the electronic device may also store tireinformation and history, and a processor or interrogator may look uppast values for the difference between the emitted and reflected wave tocalculate tread wear. Such data may be stored in a lookup table used tocalculate tread wear:

In an alternative embodiment, the electronic device sensors senses rigidparticulates within a tire tread. Examples of rigid particulatesinclude, without limitation, stones, metal (i.e., nails), and glass. Analert can be generated if the electronic device detects a rigidparticulate.

While a pneumatic tire is shown in FIG. 1, the RFID and antenna may alsobe employed in retread and non-pneumatic tire applications. The basicstructures of retread and non-pneumatic tires are known in the art andare not presented here.

FIG. 2 is a partial cross-sectional view of an alternative embodiment ofthe tire structure shown in FIG. 1. The embodiment illustrated in FIG. 2is substantially the same as the embodiment depicted in FIG. 1.Accordingly, only the differences between the embodiments are discussed.

As shown in FIG. 2, tire 200 comprises a shoulder 155, a circumferentialtread 160, a circumferential groove 165, an electronic device 170, asecond electronic device 205, and a belt region B. The electronicdevices 170, 205 are disposed radially between the belt region B and thetread surface TS of circumferential tread 160. Further, the electronicdevices 170, 205 are disposed under different lateral portions of thetire (e.g., under different ribs) so that wear may be tracked acrossdifferent segments of the tire. The electronic devices 170, 205 need notbe disposed in a common lateral plane. It should be understood that thealternative embodiments discussed with respect to tire 100 can also beemployed with tire 200.

FIG. 3 is a perspective view of one embodiment of a tire system.Specifically, FIG. 3 shows a wear-sensing system 300 for a tire.

Wear-sensing system 300 features a tire annulus 305. As shown in FIG. 3,tire annulus 305 is a tire carcass. In an alternative embodiment (notshown), the tire annulus is a green tire carcass. In another embodiment,the tire annulus is a circumferential tread. In a different embodiment,the tire annulus is a component of a non-pneumatic tire.

Tire annulus 305 features a smooth (flat) circumferential surface. In analternative embodiment (not shown), the tire annulus further comprises arecess that receives, partially or completely, a sensor. In anotherembodiment, each sensor is received by a recess.

Wear-sensing system 300 features a plurality of sensors. Specifically,FIG. 3 shows a first sensor 310, a second sensor 315, and a third sensor320. A fourth sensor in the plurality of sensors, disposed opposite tosecond sensor 315 on tire annulus 305, is hidden from view. In analternative embodiment (not shown), exactly two sensors constitute theplurality of sensors. In another embodiment, exactly three sensorsconstitute the plurality of sensors. In yet another embodiment, theplurality of sensors comprises at least five sensors.

As shown, the plurality of sensors is disposed radially above any metalstructures within the tire annulus. In an alternative embodiment (notshown), the plurality of sensors is disposed within the tire annulus. Ina different embodiment (not shown) where the tire annulus is acircumferential tread, the plurality of sensors is disposed within thecircumferential tread.

As depicted, the sensors in the plurality of sensors are disposedsubstantially equidistantly around the tire. Thus, the sensors arespaced according to the following formula:

$S = \frac{2\pi\; r}{n}$

wherein:

S=the distance between each sensor (in m),

r=the radius of the tire annulus (in m), and

n=the number of sensors in the plurality of sensors.

In practice, it should be understood that exactly equidistant spacingmay not be necessary, and sensors may be spaced within the followingtolerance:

$S = {2\pi\;{r\left( {\frac{1}{n} \pm \frac{1}{5\; n}} \right)}}$

In an alternative embodiment (not shown), the sensors are spacedaccording to the following formula:

$S = {2\pi\;{r\left( {\frac{1}{n} \pm \frac{1}{20\; n}} \right)}}$

In an alternative embodiment (not shown), at least two sensors in aplurality of sensors are disposed on a common axial edge of thecircumferential tread. As one of ordinary skill in the art willunderstand, disposing at least two sensors of a plurality of sensorsalong a common axial edge of the circumferential tread allows wearsensing along at least a portion of the axial edge of a tire footprint.Likewise, one of ordinary skill in the art will understand thatutilizing additional, overlapping sensors allows for averaging of sensorreadings. In embodiments utilizing two or more sensors, the wear sensedby both sensors can be compared, and an uneven-wear alert can begenerated if the readings differ by a predetermined amount.

FIG. 4 is a perspective view of radar and interrogator assembly 400.Assembly 400 comprises at least one radar sensor 405 and at least oneinterrogator 410. The radar sensor 405 is disposed within the frontright tire of vehicle V. In an alternative embodiment (not shown), atleast one radar sensor is disposed within each tire of the vehicle. In adifferent embodiment, two or more radar sensors are disposed on afraction of the tires on the vehicle.

Interrogator 410 powers radar sensor 405 and communicates withadditional components. Examples of additional components include,without limitation, vehicle V, a computer, a phone, a tablet, or otherelectronic device.

As depicted, interrogator 410 is disposed in a wheel well of vehicle V.In an alternative embodiment (not shown), the interrogator is disposedon a vehicle location selected from the group consisting of an axle, awheel, and a wheel well. In another embodiment, the interrogator is ahand-held device. In a different embodiment, the interrogator isdisposed on a vehicle path on which vehicles are driven. Examples ofvehicle paths include, without limitation, driveways, garage entrances,gas stations, service stations, toll booths, and weigh stations. Theinterrogator may be disposed on a post, a pad (over which a vehicle isdriven), or secured to an existing structure.

Although not shown, the radar sensor emits and receives radar waveshaving a frequency between 90 and 100 GHz. In another embodiment, theradar sensor emits and receives radar waves of a frequency between 92and 95 GHz.

Although not shown, the radar sensor emits has an emission range limitof about 1 meter. In another embodiment, the radar sensor emits has anemission range limit of about 3 meters.

Information from the interrogator or a component that has communicatedwith the interrogator may be sent to various destinations. Exemplarydestinations include, without limitation, a vehicle, the electronicdevices discussed above, a database, an original equipment manufacturer(such as a vehicle or tire manufacturer). As one of ordinary skill inthe art will understand, the data may be used for predictivemaintenance, warning systems, or quantitative analysis of tireperformance.

As one of ordinary skill in the art would understand, the tireembodiments described in this disclosure may be configured for use on avehicle selected from the group consisting of motorcycles, tractors,agricultural vehicles, lawnmowers, golf carts, scooters, airplanes,military vehicles, passenger vehicles, hybrid vehicles, high-performancevehicles, sport-utility vehicles, light trucks, heavy trucks, heavy-dutyvehicles, and buses. One of ordinary skill in the art would alsounderstand that the embodiments described in this disclosure may beutilized with a variety of tread patterns, including, withoutlimitation, symmetrical, asymmetrical, directional, studded, andstud-less tread patterns. One of ordinary skill in the art would alsounderstand that the embodiments described in this disclosure may beutilized, without limitation, in high-performance, winter, all-season,touring, non-pneumatic, and retread tire applications.

To the extent that the term “includes” or “including” is used in thespecification or the claims, it is intended to be inclusive in a mannersimilar to the term “comprising” as that term is interpreted whenemployed as a transitional word in a claim. Furthermore, to the extentthat the term “or” is employed (e.g., A or B) it is intended to mean “Aor B or both.” When the applicants intend to indicate “only A or B butnot both” then the term “only A or B but not both” will be employed.Thus, use of the term “or” herein is the inclusive, and not theexclusive use. See, Bryan A. Gamer, A Dictionary of Modem Legal Usage624 (2d. Ed. 1995). Also, to the extent that the terms “in” or “into”are used in the specification or the claims, it is intended toadditionally mean “on” or “onto.” Furthermore, to the extent the term“connect” is used in the specification or claims, it is intended to meannot only “directly connected to,” but also “indirectly connected to”such as connected through another component or components.

While the present disclosure has been illustrated by the description ofembodiments thereof, and while the embodiments have been described inconsiderable detail, it is not the intention of the applicants torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. Therefore, the disclosure, in its broaderaspects, is not limited to the specific details, the representativeapparatus and method, and illustrative examples shown and described.Accordingly, departures may be made from such details without departingfrom the spirit or scope of the applicant's general inventive concept.

What is claimed is:
 1. A tire structure comprising: a first annular beadand a second annular bead, a body ply extending between the firstannular bead and the second annular bead, a circumferential beltdisposed radially above the body ply and extending axially across aportion of the body ply, a circumferential undertread disposed radiallyabove the circumferential belt and extending axially across a portion ofthe body ply, a first sidewall extending between the first annular beadand a first shoulder, the first shoulder being associated with thecircumferential undertread, a second sidewall extending between thesecond annular bead and a second shoulder, the second shoulder beingassociated with the circumferential undertread, and an electronic devicedisposed radially between the circumferential belt and a bottom treadsurface such that wear does not disable or damage the electronic device,wherein the electronic device includes: an emitter configured to emitpulsed electromagnetic waves having a frequency between 30 and 300 GHzand a bandwidth between 15 and 35 ps; a receptor configured to receivereflected electromagnetic waves; a processor that compares at least oneproperty difference between an emitted and reflected wave; and atransmitter configured to transmit data to an interrogator, wherein theelectronic device observes wear over the life of the tire, atsub-millimeter resolution.
 2. The tire structure of claim 1, wherein theemitter is embedded within the circumferential undertread.
 3. The tirestructure of claim 1, wherein the emitter is disposed on a radiallyouter surface of the circumferential undertread.
 4. The tire structureof claim 1, wherein the emitter is resettable.
 5. The tire structure ofclaim 1, wherein real time data from the emitter is sent to a vehiclefor recordation or display.
 6. The tire structure of claim 1, whereinthe emitter is disposed within a circumferential tread, thecircumferential tread being disposed radially above the circumferentialundertread and extending axially across a portion of the body ply. 7.The tire structure of claim 1, wherein the tire structure furthercomprises a second emitter disposed radially above the circumferentialbelt.